diff mbox series

[4/5] xfrm: validate new SA's prefixlen using SA family when sel.family is unset

Message ID 20241022092226.654370-5-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit 3f0ab59e6537c6a8f9e1b355b48f9c05a76e8563
Delegated to: Netdev Maintainers
Headers show
Series [1/5] xfrm: extract dst lookup parameters into a struct | expand

Checks

Context Check Description
netdev/series_format warning Pull request is its own cover letter; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: edumazet@google.com pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 19 this patch: 19
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 18 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-10-23--12-00 (tests: 777)

Commit Message

Steffen Klassert Oct. 22, 2024, 9:22 a.m. UTC 
From: Sabrina Dubroca <sd@queasysnail.net>

This expands the validation introduced in commit 07bf7908950a ("xfrm:
Validate address prefix lengths in the xfrm selector.")

syzbot created an SA with
    usersa.sel.family = AF_UNSPEC
    usersa.sel.prefixlen_s = 128
    usersa.family = AF_INET

Because of the AF_UNSPEC selector, verify_newsa_info doesn't put
limits on prefixlen_{s,d}. But then copy_from_user_state sets
x->sel.family to usersa.family (AF_INET). Do the same conversion in
verify_newsa_info before validating prefixlen_{s,d}, since that's how
prefixlen is going to be used later on.

Reported-by: syzbot+cc39f136925517aed571@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_user.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 55f039ec3d59..8d06a37adbd9 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -201,6 +201,7 @@  static int verify_newsa_info(struct xfrm_usersa_info *p,
 {
 	int err;
 	u8 sa_dir = attrs[XFRMA_SA_DIR] ? nla_get_u8(attrs[XFRMA_SA_DIR]) : 0;
+	u16 family = p->sel.family;
 
 	err = -EINVAL;
 	switch (p->family) {
@@ -221,7 +222,10 @@  static int verify_newsa_info(struct xfrm_usersa_info *p,
 		goto out;
 	}
 
-	switch (p->sel.family) {
+	if (!family && !(p->flags & XFRM_STATE_AF_UNSPEC))
+		family = p->family;
+
+	switch (family) {
 	case AF_UNSPEC:
 		break;